docs: def bresenham_circle_octant(radius):
      """
      Uses Bresenham's algorithm to draw a single octant of a circle with thickness 1,
      centered on the origin and with the given radius.
      :param radius: The radius of the circle to draw
      :return: A list of integer coordinates representing pixels.
      Starts at (radius, 0) and end with a pixel (x, y) where x == y.
      """
      x, y = radius, 0
      r2 = radius * radius
      coords = []
      while x >= y:
          coords.append((x, y))
          y += 1
          if abs((x - 1) * (x - 1) + y * y - r2) < abs(x * x + y * y - r2):
              x -= 1
      # add a point on the line x = y at the end if it's not already there.
      if coords[-1][0] != coords[-1][1]:
          coords.append((coords[-1][0], coords[-1][0]))
      return coords